Caption: Chagas disease. Light micrograph of a section through clusters (small clumps of purple bodies) of Trypanosoma cruzi protozoans in the heart muscle of a patient suffering from Chagas disease. These protozoa (single-celled organisms) are in the amastigote form, which lives inside the cells of tissues such as the brain, heart and liver, multiplying rapidly. Symptoms of Chagas disease include fever, enlargement of the liver, oesophagus and colon and inflammation of the heart muscle. The destruction of the many tissues invaded by T. cruzi can cause death. Magnification unknown.